document.write( "Question 1101510: Need help solving the oblique triangle.\r
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\n" ); document.write( "side b = 5\r
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Algebra.Com's Answer #716118 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Since sides a and b are both equal, ΔABC is isosceles,\r\n" );
document.write( "and ∠A = ∠B.  Suppose ∠A = ∠B = x,\r\n" );
document.write( "then since ∠A+∠B+∠C = 180°,\r\n" );
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document.write( "x + x + 30° = 180°\r\n" );
document.write( "   2x + 30° = 180°\r\n" );
document.write( "         2x = 150°\r\n" );
document.write( "          x = 75°\r\n" );
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document.write( "Therefore ∠A and ∠B are 75° each.\r\n" );
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document.write( "To find the length of side c, we draw the median CD (in green),\r\n" );
document.write( "which since ΔABC is isosceles, is also the perpendicular\r\n" );
document.write( "bisector of side c and the bisector of ∠C.\r\n" );
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document.write( "Therefore ΔBCD is a right Δ, and ∠BCD = 15°. \r\n" );
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document.write( "We also know that BD is half of AB which is side c.\r\n" );
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document.write( "We multiply both sides by 5\r\n" );
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document.write( "Using calculator:\r\n" );
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document.write( "Side c is twice that or\r\n" );
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document.write( "You can round it however you were told.\r\n" );
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document.write( "Edwin

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